U.S. Pat. Nos. 4,723,257 and 4,665,529 disclose a solid-state laser pumped at one end by means of a laser diode array via a light-conducting fiber. The solid-state laser includes a focusing lens for the pump light. The laser medium is Nd--YAG or the like. For laser rod dimensions of 3 mm in diameter and 5 mm in length, the complete laser head, including a frequency doubler crystal, has a diameter of approximately 1 cm and a length of approximately 8.4 cm. A reduction in size of 32% to 50% is, however, indicated as being possible. A pilot beam is not provided.
U.S. Pat. No. 4,808,789 discloses a laser instrument suitable for surgery. The laser instrument includes a diode pumped Nd--YAG laser or the like wherein the laser beam is conducted to a handheld stylus via light-conducting fibers. The handheld stylus has a frequency doubler crystal and a zoom objective for focusing. A gas flow can exit from the conically-shaped end of the handheld stylus coaxially to the laser beam. An erbium laser completely integrated into a handheld stylus is also described. The erbium laser (FIG. 2) includes an axially arranged laser diode array as the pump source and is without optical fibers. The arrangement is intended to be compact but specific dimensions are not provided. The entire laser arrangement including battery is intended to be held in the housing shown; however, it cannot have a diameter of only a few millimeters.
U.S. Pat. No. 5,198,926 discloses a surgical laser device having a visible target beam and an IR-power beam having a wavelength of 3 .mu.m or more. The beams are focused via an achromatic objective onto a common point. The achromatic objective is made of suitable material. Superposition takes place with a dichroic mirror.
U.S. Pat. No. 5,214,664 discloses a coaxially emitting multiple wavelength solid-state laser. The solid-state laser here includes a laser diode of the Ga--As type. The wavelengths of 778 nm and 843 nm are mentioned as exemplary. However, it is not possible to derive a simultaneous emission in the visible and the mid IR-range from the disclosure of this patent.
U.S. Pat. No. 4,917,486 discloses a photocoagulator based on a slit lamp. The photocoagulator has an IR-laser diode and visible laser diode for the target beam which is superposed by means of a dichroic mirror.
Although light conductors for the wavelength of erbium lasers (approximately 3 .mu.m) are obtainable (ZBLAN-fibers), they are, however, problematical because they can be toxic (material: fluoride), expensive and do not sustain much use.
U.S. Pat. No. 5,123,845 discloses a dental laser arrangement having a solid-state laser which is pumped laterally via flash lamps. For example, the solid-state laser can be an erbium laser which is coaxially transilluminated by a He--Ne-target laser which is transmitted to a handheld member for treatment via a light conductor transmitting unit. This configuration can in no way be compact and the difficulty of the light conductor with respect to the wavelength of the erbium laser in not eliminated.